An apparatus of this type has already been developed by the Applicant and is described, in particular, in PCT International Application published under the number WO91/07662.
In summary, that apparatus comprises:
a sample module comprising a plurality of tubes containing the samples to be analyzed and carried by a rotary turntable or ring;
a reagent module comprising a rotary turntable or ring supporting tubes containing the reagent(s) used for the analyses to be performed, at least one of said reagents being in the form of magnetic particles;
a reaction module comprising a rotary turntable or ring carrying a plurality of tubes or vessels each intended to receive a determined quantity of a sample and a determined quantity of an appropriate reagent, a washing device being associated with said reaction module;
drive means for driving said modules in stepwise rotation;
means enabling the desired quantities of samples and of reagents to be conveyed to the reaction vessels or tubes;
means suitable for reading the results of reactions performed in the reaction vessels or tubes; and
a computer system for controlling the various modules and their drive means, to perform a succession of analysis cycles.
Each analysis cycle comprises a series of steps constituting at least one immunological incubation, and a series of steps constituting a developing incubation, in particular an enzymatic incubation, each step corresponding to a number of sequential positions of a reaction vessel or tube in the reaction module, the stop time of a reaction vessel or tube in any one position being constant.
The washing device associated with the reaction module serves to wash the above-mentioned magnetic particles between incubations.
That apparatus has the advantage of enabling ELISA, RIA, FIA, LIA, FPIA, CLIA, etc. techniques to be fully automated and it is particularly applicable to detecting ligands, antiligands, haptens, or any other biological or non-biological substance that may optionally be present in a single sample to be analyzed.
That apparatus also has the following advantages:
it is possible to perform random access multi-parameter assay of samples;
it is possible to obtain a high assay rate (e.g. 100 assays in 50 minutes); and
the set of reagents can be calibrated using a multi-parameter calibration agent.
In one embodiment of that apparatus, the reaction module supports four groups of 25 reaction vessels, i.e. a total of 100 vessels, and each complete operating cycle of the apparatus corresponds to processing 100 vessels, i.e. 99 assays and 1 control. At the end of each cycle, the apparatus stops and the operator needs to withdraw the four groups of 25 vessels that have been used, to replace them on the reaction module with four groups of new vessels, to withdraw the tubes containing samples whose assays have just been performed from the sample module and replace them with tubes containing new samples to be analyzed, and to key in a new work list on the control keyboard of the computer system (patient name(s), types of assays to be performed, etc.). Since the groups of vessels are fixed on the rotary turntable of the reaction module, they can be replaced only when the apparatus is fully stopped. Altogether the above operations take up about 15 minutes, thereby slowing down the operating rate of the apparatus in the long run.
In order to avoid stopping the apparatus at the end of each operating cycle, it would naturally be possible to leave the reaction vessels on the reaction module and to associate vessel-cleaning means with the module. Nevertheless, that would require the number of successive positions through which each of the reaction vessels passes to be increased, since cleaning operations must necessarily be performed in a plurality of steps, and that would increase the duration of each operating cycle of the apparatus so no time would be saved.